It is well known that ink script can be removed, even if only partially, when it is subjected to suitable chemical or physical action such as, for example, abrasion by bladed instruments or fine points, decolouration with suitable oxidising/reducing agents (including the common "ink-eradicators"), laser light, etc.
It is equally well known that there are recognised solvents or mixtures of solvents which are able to remove script, whatever ink has been used, without etching into the substrate to which it has been applied and hence without leaving any obvious trace of the removal.
In order to protect ink script, particularly but not exclusively on official documents, bank cheques and other similar documents, from accidental or intentional removal, particularly when this is unauthorised, many techniques and devices have been proposed among which are the covering of the script with a transparent film which is extremely adhesive to the paper substrate, which is unaffected by the type of ink used for the script itself and which is insoluble in the solvents for such ink.
However, at least with regard to intentional unauthorised deletion, the techniques and devices adopted up till now have had limited success over time and in the field of application, that is, they have been useful until countermeasures have been found to overcome their protectiveness.
A need has therefore been felt to prevent ink script whether effected manually with a fountain pen, ballpoint pen, felt pen, stamp or the like, or mechanically with a printer, ink jet printer, post marking machine or the like, from being deleted, even only partially, either accidentally or intentionally.